Electrical system



Feb. 13, 1940. L. P.'MORR|S ELECTRICAL SYSTEM 2 Sheets-Sheet 1 Filed Jan. 15, 1935 Feb. 13, 1940. MORRIS 2,189,990

ELECTRICAL SYSTEM Filed Jan. 15, 1935 2 Sheets-Sheet 2 A A A A A A A A A A A A A A A l A A n v v v v v I I v v v v v v v I v I I v n Patented Feb. 13, 1940 UNITED STATES PATENT OFFICE ELECTRICAL SYSTEM Application January 15, 1935, Serial No. 1,910

7 Claims.

My invention relates in general to electrical systems for supplying electrical. power at relatively high voltage from a relatively low-voltage power source, the invention having more particular reference to improved means for and methodof converting relatively low-voltage direct-current power, such as may be supplied from a storage battery, into power at relatively higher potential for any desired purpose.

The invention relates, more specifically, to an improved power converter particularly adapted for use in radio-equipped vehicles for the purpose of providing power, at the relatively highvoltage necessary to the operation of the radio apparatus, using the relatively low voltage power source of the vehicle ignition or lighting system as the original power source for energizing the system.

Another important object is to utilize circuitchanging means of improved construction in conjunction with a transformer and a directcurrent power source in order to produce alternating current, in the secondary circuit of the transformer, at relatively higher voltage than is supplied to the primary circuit from the direct-current power source, so that, by rectifying the fluctuating current in the secondary circuit of the transformer, unidirectional current at relatively high potential may be made available;

a further object being to provide a rectifier comprising a vibrating reed, the period of vibration of which increases with an increase in applied voltage, whereby the rectifying characteristics of the device are improved.

Another important object is to provide circuitchanging means embodying a vibrating reed and contact-carrying blades operatively associated with the reed, whereby the same alternately engages the blades, and wherein the reed and 40 blades are supported in a base comprising moldable material of the character providing a highresistance leakage path between the reed and the associated blades, this highesistance path being adapted to permit the 10 s of high-fre- 45 quency modulations in the current carried by the blades.

Another important object is to provide circuitchanging means comprising a vibrating reed disposed between a pair of current-carrying 5 blades, and adapted, when vibrated, to alternately contact the blades, the reed being designed to vibrate about a fictitious fulcrum therein which moves toward the vibrating end of the reed as the voltage, applied between the 55 reed and the blades, increases.

Another important object resides in simplifying the construction of vibratory circuit changers by mounting the vibrating reed of the changer and its associated contacts in a block of moldable material, so that the reed, its assoz, ciated blades, and the mounting comprise an assembly unit; a further object being to provide a frame in which the elements may be mounted, the frame comprising simply a sheet-metal channel element adapted to snugly receive the in blade and-reed as an assembly unit therein, with the blades and reed extending and housed within the channel, the mounting being received in the channel at one end thereof and being secured by means of a holding plate interfittingly 15 received between the sides of the channel member and serving to rigidity the same.

A further object is to provide a vibrating coil in a device of the character mentioned and to mount the coil on a frame adapted to be de- 20 mountably secured on the channel member in the end thereof opposite from the reed and blade mounting and in position opposite the free end of the reed.

A still further object is to provide readily 25 adjustable means in the opposite side walls of, the channel member in position to co-operate with the blades and adjust the relative position thereof with respect to the vibrating reed.

Another important object is to form the blade 30 and reed mounting with ridges extending in a surface thereof between the reed and the blades in order to provide high creepage characteristics to prevent electrical creepage leaks in the surface of the mounting between the blades and '85 the reed.

A still further object is to form the reed as a blade having an end formed to facilitate the embedding thereof in the moldable material forming the reed mounting, this blade end hav- 40 ing a perforation into which the material of the moldable material may enter in order to securely lock the part in place, the reed-forming plate also having a finger projecting beyond the surface of the reed mounting in order to facilitate electrical connection with the reed on the side of the mounting opposite from the vibrat ing portion of the reed, and a further object is to form the contact blades in like manner.

A still further object is to arrange the blade and reed mounting in the channeled member in position spaced from an end thereof sufiiciently to conceal the contact-making ends of the reed and blades within the zone of the channel member in order to protect the same.

Yet another important object is to utilize the clamp member by -means of which the reed mounting is secured in the casing, for the purpose of holding an end of an insulation flap in position to overlie the exposed terminal ends of the reed and blades.

Another important object is to enclose the open side and ends of the channel member by means of a cover comprising preferably a sheet-metal strip, the opposite ends of which are bent to overlie the opposite ends of the channelled member and to underlie therewith in order to secure the cover in place.

Another important object resides in the provision of a sheath of resilient material by means of which the circuit changer may be resiliently suspended in a canister.

Another object is to provide a circuit changer embodying opening and closing contacts and having means incorporated therein to suppress undesired voltage modulations initiated therein as a result of electrical disturbances set up at the contacts during the opening and closing of the same; a further object being to provide built-in capacitive means for the suppression of so-called hash, as undesired voltage modulations are frequently termed.

Another object is to utilize the hash suppressing condensers to assist in tuning the circuit so as to reduce the voltage across the contacts of the changer at the instant that the same opens or closes in order to reduce, hash caused by sparking to a minimum.

Another important, object is to provide a hash suppressing condenser for electrical systerns wherein the frame, on which the condenser is mounted, forms one plate of the condenser; a further object being to provide for grounding one plate of a hash suppressing condenser by utilizing a grounded frame as one plate of the condenser.

Another object resides in utilizing a metallic plate-like holder, clip, or clamp to support acondenser plate and dielectric layers in stacked relationship on a grounded frame, the clamp. being electrically connected to the frame so that the clamp itself functions as a grounded plate to increase the capacitance of the condenser.

Another object is to provide a neat compact condenser structure, which may be assembled on a support frame in position close to a. device to which the condenser is to be connected so as to eliminate the necessity of long condenser leads.

Numerous other objects and advantages of the invention will be apparent from the following description, which, taken in connection with the accompanying drawings, discloses preferred embodiments of the invention.

Referring to the drawings:

Figure l is a perspective view of a circuit changer unit embodying the present invention;

Figure 2 is a sectional view taken substantially along line 2-2 in Figure 1; I

Figure 3 is a perspective view of a canister for housing the device;

Figure 4 is a perspective view of a resilient sheath and cover for enclosing the circuit changer within its canister housing;

Figure 5 is a perspective view illustrating the circuit changer and its cover in disassembled relationship;

Figure 6 is a perspective view of the vibrating reed and blade assembly unit forming the circuit changem Figure"! is a perspective view of a resilient metal plate comprising the vibrating reed; and Figure 8 is a perspective view of a blade, both plate and blade forming parts of the assembly units shown in Figure 6; p

Figure 9 is a plan view of a condenser forming a part of the device;

Figure 10 is a sectional view taken substantially along the line Ill-I0 in Figure 9; and

Figure 11 is a schematic wiring diagram showing the manner of connecting the device for operation. To illustrate my invention, I have shown in Figure 11 a power-supply system comprising a transformer Ill and a circuit changer ll interconnected in such a fashion that direct-current power delivered to the, system may be transformed and re-delivered by the system at a relatively higher voltage. Thecircuit changer H is preferably of elongated prismatic shape, the form shown being square in cross-sectional configuration.

Referring to the drawings, the device II is enclosed in a canister l2 and is enclosed in a resilient sheath I3 within the canister. The sheath comprises a preferably cylindrical block l3 of resilient material, such as sponge rubber, the block having a socket opening at one end of the block and adapted to receive the circuit changer H. The circuit changer may be inserted into the block through the open end of the socket and a cover I4 is provided to close the open end. The cover and block l3 have interfitting grooves to assist in retaining, within the sheath, any noise developed during operation of the circuit changer. The outer walls of the sheath are grooved as at I6 to receive connectors 18 extending from the device ll through openings 20 in the sheath adjacent the cover I4, thence in the grooves 16 to the opposite end of the sheath where the conductors are connected to prongs 22 on the cover 24 ofthe canister.

The circuit changer II is adapted for use in conjunction with a transformer It), being connected therewith by means of the prongs 22,

which are adapted to co-operate with a receptacle 26, the terminals of which are connected with the transformer Ill. The transformer has a primary winding [5 provided with a. tap connection l1 and a secondary winding l9 also provided with a tap connection 2|.

, The circuit changer I l is assembled in a frame 51 and comprises a pair of spaced primary contacts 23, 23 and contact means 25 intermediate the spaced contacts and adapted to alternately engage the same. The contacts 23, 23' are respectively connected, by conductors ,2! which extend in the grooves Hi, to the opposed ends of the primary coil l5 of the transformer.

The circuit changer also comprises a second pair of spaced contacts 33, 33' corresponding to the contacts 23, 23' and intermediate shiftable contact means 35 adapted to alternately engage opposed ends of thesecondary winding IS. The intermediate shiftable contact means 25 is connected to one side, preferably the negative side, of a direct-current power source A, the other side of which source is electrically connected with the tap connection ll of the primary coil [5. With such an arrangement 'by oscillating the contact means 25 so that the same alternately engages the spaced contacts 23, 23', current will be caused to flow alternately through the primary coil portions extending from the top the spaced contacts 33, 33'. The contacts 33 and 33 are connected as by conductors 31 with theconnection ill on opposite sides of the tap connection. The current thus flowing alternately and in opposite directions in the primary coil l will induce an alternating electrical current in the secondary coil l9. If desired, the alternating-current power may be taken off directly from the coil it for use in a load circuit employing alternating current. For operating a direct-current load circuit, however, I provide for rectifying the alternating current induced in the secondary circuit by means of the contacts 33, 35 and 35. To this end, means is provided for causing the contact means 35 to oscillate between. the contacts 33 and 33' in timed or synchronized relationship with the movement of the contact 225. The contacts are adjusted, however, so that the contact 25 engages the contacts 23, 23' slightly in advance of the respective engagement of the contact 35 with its associated contacts 33, 33'. I prefer to accomplish this by mounting the contacts 25 and 35 for movement between their associated contacts 23, 23' and 33, 33 on a common carrier blade or reed 45. Since the secondary coil is connected with the contacts 33 and 33, the oscillation of the movable contact 35 therebetween will cause circuits to be made and broken, so that substantially uni-directional current will be delivered between the contact means 35 and the secondary tap connection 25.

The contacts 25 and 35 also are preferably electrically connected together and grounded, one side of the power circuit A and of the load circuit being likewise grounded. It will be apparent, however, that the invention may, with equal facility, be applied to an ungrounded system if desired. The uni-directional current so delivered, between the contact 35 and the tap it, to the load circuit B, will have a potential different from that applied between the contact means 25 and the tap connection ll] of the primary coil, the ratio between applied and deiivered potential being substantially the ratio of turns in the primary coil to turns in the second= ary coil. If desired, the tap connection it of the secondary coil may be connected with filter means 2ft comprising a series-parallel network of inductive and capacitive reactance means, the purpose of the filter being to smooth out voltage fluctuations in the direct current delivered between the contact means 35 and the tap it in series through the filter means 29.

It will be noted that with ,the connections ".lOWIl in Figure ll, in which the tap ill is connected to A positive and the contact 25 to A negative, the contact 35 becomes the negative load connection while the secondary tap it becomes the B positive terminal. 'I may reverse the polarity of the load terminals simply by reversing the connections of the contacts and with the secondary coil it.

The contacts 2t and 33, 33 preferably comprise buttons of electrical conducting material mounted each on a separate blade M, iilustrated in Figure 8, and comprising resilient strips of electrical conducting material. The contact means 25 and 35 may vlikewisecomprise similar buttons and mounted all on a common blade or reed 35 comprising a resilient strip of electrical conducting material as shown in. Figure 7. These contact buttons are preferably mounted in pairs on preferably resilient mounting strips ti secured on opposite sides of the blade or reed Q5. The buttons adapted to engage contacts 23 plate All, while the buttons adapted to engage and 33 are on one mounting contacts 23' and 33 are on the other mounting strip. The blades 4| and 45 are all preferably supported at one end in a mounting block 49, preferably of a suitable moldable insulating material such as a'phenolic condensation product.

The blades 3| and the blade 45 are separated on and extend from a surface of the mounting block 49 in proper relative position, so that the contact button on each blade 4! registers with a corresponding button carried on the blade 45. When the blade 45 is vibrated, the buttons, forming the contact means 25 and 35, alternately engage the buttons forming the spaced contacts 23, 23' and 33, 33', respectively, in order to perform the rectifying function heretofore described. In order to cause the reed or blade 45 to oscillate, and thus make and break contact between the contact buttons, I provideian actuating coil 50 having a core 53 providing a pole extending substantially opposite the free end of the blade 45. The coil 5! is mounted on a frame 52, which may be secured to the bottom of the channel member 5'! by means of fastening screws 54.

I also mount, upon the free end of the blade 55, an armature 55 preferably comprising a strip of ferrous metal. The blade 45 normally supports the armature 55 in an eccentric position with respect to the end of the pole 53 of the actuating coil, so that by periodically energizing the coil 55, the armature 55 may be drawn to a position opposite the end of the pole 53, thus moving the end of the blade t5 a distance sufficient to bring the contact means 25 and 35 into engagement respectively with the contact 23' and the contact 33.

I also provide for de-energizing the coil as soon as contact is thus made in order to permit the resilience of the blade d5 to move the blade a sufficient distance so that the contact means 25 and come into engagement respectively with the other contacts 255 and This may be accomplished by connecting the coil M between the contact tii' and the side of the power source other than the side which is connected to the tap Gil.

It will thus be seen that direct-current power will be delivered through one-half of the coil 95 and through the coil M in series. As soon as the contact means 25, which is connected to the power source, engages the contact 23', the coil 5i, which preferably has relatively high impedance, is short-circuited and hence immedi-v ately becomes ale-energized and releases the armature 55 and the blade t5. This blade, because of its resilience, immediately breaks the contact between the contact means 25 and 35 and the contacts 23 and 33', and moves to a position making contact with the contacts 23 and 3353. As soon as this happens, however, the coil 56 is no longer short-circuitedand is again energirzed to draw the blade Q5 into position to engage the contacts 25 and 35 with the contacts 223' and 33', whereupon the cycle is repeated.

I prefer to pre-form the blades i l and 45 and their mounting til as a unit and to assemble the unit in a support frame 5i, comprising an elongated channel-shaped element. The moldable base til, in which the blades ll and are mounted, is shaped to fit snugly between the opposite side walls of the channel member 57 and the same is retained in place by means of a holding plate 5%, the opposite ends M of which have preferably dove-tailedinterfitting relationship in slotted portions formed in the edge of the op- Ill till

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posite side walls ofthe channelled member 51 near one end thereof. The base 49 is clampingly received between the plate 59 and the bottom wall of the channelled member 51, the plate being held in place by means of fastening studs 53, which are inserted through perforations formed in the bottom" wall of the channelled member and extend through slots 65 formed in the opposite edges of the rectangular support element 49, the holding studs threading into perforations 51 formed in the holding plate 59.

The embedded ends of the blades 4| and 45 are preferably of reduced width to form terminals 69, and the blades. are mounted in the mounting block 49 with their terminal ends 59 extending outwardly of 'a surface of the block in order to facilitate electrical connections with the contacts 23 and 33 and with the contact means and 35, which connections are accomplished through the blades 4| and 45. It will be noted that the mounting block 49 is disposed in such position that the projecting terminals 69 are entirely within the zone of the channelled member 51 at one end thereof, and the clamp plate 59 is utilized to secure a flap of flexible insulating material 1| so that the same may be drawn down to cover the terminals 69 as shown in Figure 5.

Co-operating means is provided in the opposite walls of the channelled member 51 and on the blades 4|, whereby the position of the blades, with respect to the blade 45, may be adjusted in order thus to adjust the relative spacing of the contact buttons 23, 23, 33 and 33" with respect to the associated buttons 25 and 35. To this end, the free ends of the blades 4| are provided with bearing blocks 13, which are preferably of non-conducting material, and secured in openings 15 formed in the ends of the blades 4|, these bearing blocks serving to rest upon the inner ends of adjustable set screws 16 threadedly extending in openings formed in the opposite walls of the channelled member 51 in position to register with the bearing blocks 13. The resilience of the blades 4| normally urges the same outwardly toward the adjusting screws 15 and presses the bearing blocks against the screws. By turning the screws 15 in the walls, the end of each blade may be adjusted to a desired position in order to determine the position of the contact buttons 23, 23', 33, and 33 with respect to their associated shiftable contacts 25 and 35 on the blade 45, and in order that during vibration of the reed, the contact 25 will engage the contacts 23 and 23 slightly in advance of the engagement of the contact 35 with the contacts 33 and 33'.

Channelled member 51 is preferably formed of sheet metal, and, if desired, the wall portions, in which the adjusting screws 15 are mounted, may be embossed inwardly as shown at 11 in order to depress the outwardly facing ends of the screws below the outer surface of the frame member 51. The projecting heads of the fastening screws 54 and 63, however, may be received in depressions 18 formed in the sheath I3.

A corner of the mounting block 49 is preferably cut away to permit a conductor 83 to extend within the channelled member 51 from the coil 5| to the terminal 69 of the blade which carries the contact 23' to which the coil is connected.

The other end of the coil may be grounded by attaching the same to the frame 51 as at 85, and the blade 45 is likewise preferably grounded to the frame 51 as at 86.

cut away as at 81 to permit conductors I8 to extend from the terminals 59 through the openings 20' and the grooves I6 of the casing I3 as shown in Figure 2. A cover 9I,. comprising a strip of sheet metal having a central portion adapted to overlie the opening between the upper edges of the side walls of the channel member 51 and resilient dependent ends 93 adapted to overlie and embrace the open ends of the channelled member, is provided for enclosing the contacts, blade mounting, blade terminals, and the actuating coil 5|. The cover 9| has dependent marginal flanges 95 adapted to interlock with the upper edges of the side walls of the channel member 51, and also has inwardly extending flanges 91 at the free edges of the cover portions 93, these flanges being adapted to look behind the bottom wall of the channel member in order to secure the cover in place thereon.

In order to prevent high-frequency modulations, which may become impressed upon the apparatus, particularly when the same is used in an automobile for operating a radio receiver therein, and which will seriously impair the oping such high-frequency modulations by connecting a condenser 99, as shown by dotted lines in Figure 11, between the opposite ends of the secondary coil I9, the condenser connections being preferably as short as possible. I prefer, however, to accomplish the suppression of high-frequency modulations by grounding the opposite ends of the transformer secondary coil I9 through condensers II", which preferably each comprise a thin film I03 of dielectric material, such as paper, secured to an inner surface of the side walls of the channel-shaped frame 51, and a condenser plate I05 secured on the side wall with the dielectric I03 between the plate I05 and the side wall of the frame. The plates I05 and dielectric layers I03 may be held in place on the frame by means of a clip I08 having .arms I01 adapted to interlock in perforations I08 formed in the walls of the support frame 51. An insulating layer I04 is arranged between the plate I05 and the body of the clip I05 and, since the clip is connected electrically with the frame 51, the condenser capacitance is substantially doubled because the clip forms a condenser plate. The frame consequently forms a grounded plate of each condenser IOI, the other plates of these frame 51, I am able to simplify the construction of the condensers, eliminate parts by using the frame to form one plate of each condenser, and since the plate is itself grounded, a condenser ground connection is eliminated.

I prefer also to form the blade mounting block 49 of a material which, while being substantially an insulator, provides a high-resistance leak III between the plates supported therein. The presence of such a leak permits high-frequency losses between the contacts 23 and 33 and the blade 45, which is grounded, although low-frequency and direct-current losses are substantially prevented.

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aisaeeo In other words, the presence of the high-resistance leak provided by the mounting 49 between the blades 4! and 45, assists in the elimination of high-frequency modulations in the current delivered between the blade 45 and the secondary tap M.

An important feature of the invention resides in the fact that the blade 45, when in moderate oscillation, vibrates about a fictitious fulcrum which is substantially at or opposite the surface of the block 49, from which the blade extends. The device is particularly adapted for use in connection with six-volt storage batteries of the character usually employed in automobile ignition and lighting systems. The delivered voltage from such batteries will vary considerably from time to time, the variation being usually between limits of 5 and 9 volts, depending upon prevailing conditions of temperature, external load on the battery, and the charged condition of the battery.

The load connected to the output side of the system of my present invention is, however, substantially constant. Consequently, as the voltage of the storage battery changes, the current delivered through the system will increase. An increase in current transferred through the transformer will cause a drop in the inductance of the transformer as the same becomes magnetically saturated. As the inductance of the transformer decreases, the electrical period or frequency of the reactive system comprising the transformer and the condensers 99 or ifll becomes higher, and it is desirable to alter the frequency of vibration of the blade QB in propor tion to the increase in the periodic frequency of J the condenser-transformer network. This is accomplished in the device of my present invention -by the fact that as the voltage increases, the

dd blade 35 will be deflected more vigorously by the coil 5i], so that the amplitude of vibration of the blade is increased. As the amplitude of vibration of the blade is increased, the fictitious fulcrum, about which it vibrates, will be shifted in 45 the blade away from the mounting block 49, with the result that the vibrating length of the blade will be shortened, and its natural frequency increased. The parts are so selected that this frequency increase corresponds closely with the change in frequency of the condenser-transformer network in order that, at all times, the period of the blade will substantially correspond to the frequency period of the condenser-trans former network.

It is thought that the invention and numerous of its attendant advantages -will be understood from the foregoing description and it is obvious that numerous changes may be made in the form, construction, and arrangement of the several parts of the illustrated apparatus without departing from the spirit or scope of my invention or sacrificing any of its attendant advantages, the preferred form and mode herein described being merely for the purpose of illustrating the invention.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is as follows:

1. The combination with a transformer comprising inductively coupled primary and secondary coils, the primary coil having a central tap, a pair of primary contacts electrically connected with the primary coil on opposite sides of the tap, a shiftable primary contact operatively mounted between said contacts and adapted to alternately engage the same, and means to connect the primary tap and said shiftable contact with a source of direct current whereby to deliver uni-directional current through the primary coil from said tap alternately in opposite directions in the coil whereby to induce, in the secondary coil, current flowing therein alternately in opposite directions, and means causing the vibration of the shiftable contact to vary with the potential applied to the primary coil.

2. The combination with a transformer comprising inductively coupled primary and secondary coils, the primary coil having a central tap, a pair of primary contacts electrically connected with the primary coil on opposite sides of the tap, a shiftable primary contact operatively mounted between said contacts and adapted to alternately engage the same, and means to connect the primary tap and said shiftable contact with a source of direct current whereby to deliver uni-directional current through the primary coil from said tap alternately in opposite directions in the coil whereby to induce, in the secondary coil, current flowing therein alternately in opposite directions, and suppressor means operatively associated with said secondary coil for eliminating high-frequency voltage modulations in the current induced therein.

3. The combination as set forth in claim 2, wherein the suppressor means comprises reactive means associated with the secondary coil, said reactive means having a value such that the network is tuned to a frequency at which the voltage in the secondary circuit is approximately the same as the load voltage at the instant of contact to eliminate sparking due to inequality of voltages in the secondary and load circuits.

4. The combination as set forth in claim 2,

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wherein the suppressor means comprises capacitive means connected between the opposed ends of the secondary coil.

5. The combination as set forth in claim 2, wherein elimination of high-frequency modulations of secondary voltage is accomplished by grounding the opposite ends of the secondary coil through condenser means to the frame.

6. In combination, a frame, inductively coupled primary and secondary coils on said frame, means carried by said frame and including a pair of spaced contacts and a co-operating contact adapted to engage said spaced contacts alternately andto apply direct current through said primary coil alternately in opposite directions whereby to induce an alternating current in said secondary coil, and means for eliminating highfrequency modulations of current induced in said secondary coil comprising a condenser plate electrically connected with said secondary coil and secured on a portion of said frame with a dielectric layer between said plate and said frame portion.

7. In combination, a sheet-metal frame comprising spaced side walls and. an intermediate bottom wall, a transformer element comprising inductively coupled primary and secondary coils secured between said spaced side walls at one end of said frame, means for delivering unidirectional current alternately in opposite directions through said primary coil comprising a pair of primary contacts connected respectively to the ends of said primary coil and a primary switching contact adapted alternately to engage said primary contacts, means for connecting said primary switching contact and an intermediate portion of said primary coil with a source of bib ends of said secondary coil, said plates being mounted each on one 0! said spaced side walls, a dielectric layer interposed between each of said condenser plates and the side wall on which it is mounted,- and a clip for each condenser plate comprising a portion overlying the plate and portions interlocking with the frame to secure the plate and the dielectric layer in place on the frame.

LLOYD P. MORRIS. 

